Many different types of utilities are placed underground, such as water, communication, and electricity. The utilities are typically accessed from the surface at predetermined locations where covered vaults have been placed. In northern claimants, the temperature in side of the vaults in the winter can drop below freezing. Some utilities are adversely affected by such low temperatures. For example, water freezes causing damage to pipes and/or reduced water pressure.
What is needed in the art is an approach for maintaining the temperature in a vault above a freezing.